Merge "import copy of bpf_net_helpers.h from system/netd/bpf_progs" am: 28c51a157c

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1733033

Change-Id: If7d5655192f64b66a3175bc84ba31585a50848e0

Tethering/bpf_progs/Android.bp

@@ -48,10 +48,6 @@ bpf {
         "-Wall",
         "-Werror",
     ],
-    include_dirs: [
-        // TODO: get rid of system/netd.
-        "system/netd/bpf_progs",             // for bpf_net_helpers.h
-    ],
 }
 
 bpf {
@@ -61,8 +57,4 @@ bpf {
         "-Wall",
         "-Werror",
     ],
-    include_dirs: [
-        // TODO: get rid of system/netd.
-        "system/netd/bpf_progs",             // for bpf_net_helpers.h
-    ],
 }

Tethering/bpf_progs/bpf_net_helpers.h

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <linux/bpf.h>
+#include <linux/if_packet.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+// this returns 0 iff skb->sk is NULL
+static uint64_t (*bpf_get_socket_cookie)(struct __sk_buff* skb) = (void*)BPF_FUNC_get_socket_cookie;
+
+static uint32_t (*bpf_get_socket_uid)(struct __sk_buff* skb) = (void*)BPF_FUNC_get_socket_uid;
+
+static int (*bpf_skb_pull_data)(struct __sk_buff* skb, __u32 len) = (void*)BPF_FUNC_skb_pull_data;
+
+static int (*bpf_skb_load_bytes)(struct __sk_buff* skb, int off, void* to,
+                                 int len) = (void*)BPF_FUNC_skb_load_bytes;
+
+static int (*bpf_skb_store_bytes)(struct __sk_buff* skb, __u32 offset, const void* from, __u32 len,
+                                  __u64 flags) = (void*)BPF_FUNC_skb_store_bytes;
+
+static int64_t (*bpf_csum_diff)(__be32* from, __u32 from_size, __be32* to, __u32 to_size,
+                                __wsum seed) = (void*)BPF_FUNC_csum_diff;
+
+static int64_t (*bpf_csum_update)(struct __sk_buff* skb, __wsum csum) = (void*)BPF_FUNC_csum_update;
+
+static int (*bpf_skb_change_proto)(struct __sk_buff* skb, __be16 proto,
+                                   __u64 flags) = (void*)BPF_FUNC_skb_change_proto;
+static int (*bpf_l3_csum_replace)(struct __sk_buff* skb, __u32 offset, __u64 from, __u64 to,
+                                  __u64 flags) = (void*)BPF_FUNC_l3_csum_replace;
+static int (*bpf_l4_csum_replace)(struct __sk_buff* skb, __u32 offset, __u64 from, __u64 to,
+                                  __u64 flags) = (void*)BPF_FUNC_l4_csum_replace;
+static int (*bpf_redirect)(__u32 ifindex, __u64 flags) = (void*)BPF_FUNC_redirect;
+static int (*bpf_redirect_map)(const struct bpf_map_def* map, __u32 key,
+                               __u64 flags) = (void*)BPF_FUNC_redirect_map;
+
+static int (*bpf_skb_change_head)(struct __sk_buff* skb, __u32 head_room,
+                                  __u64 flags) = (void*)BPF_FUNC_skb_change_head;
+static int (*bpf_skb_adjust_room)(struct __sk_buff* skb, __s32 len_diff, __u32 mode,
+                                  __u64 flags) = (void*)BPF_FUNC_skb_adjust_room;
+
+// Android only supports little endian architectures
+#define htons(x) (__builtin_constant_p(x) ? ___constant_swab16(x) : __builtin_bswap16(x))
+#define htonl(x) (__builtin_constant_p(x) ? ___constant_swab32(x) : __builtin_bswap32(x))
+#define ntohs(x) htons(x)
+#define ntohl(x) htonl(x)
+
+static inline __always_inline __unused bool is_received_skb(struct __sk_buff* skb) {
+    return skb->pkt_type == PACKET_HOST || skb->pkt_type == PACKET_BROADCAST ||
+           skb->pkt_type == PACKET_MULTICAST;
+}
+
+// try to make the first 'len' header bytes readable via direct packet access
+static inline __always_inline void try_make_readable(struct __sk_buff* skb, int len) {
+    if (len > skb->len) len = skb->len;
+    if (skb->data_end - skb->data < len) bpf_skb_pull_data(skb, len);
+}